For me, at least, the worst part of working from the office (not matter how many days) is that it forces you and your family to live in a big city or near one. 2 days per week at the office and suddenly you cannot live anymore in a remote town owning a big house with your own garden… instead now you have to pay an absurd amount of money to live in a crap apartment just so you can spend less than 30 min. commuting. You have to eat shit food from a fancy restaurant most of the days, you have to listen the stupid jokes your manager makes from time to time, you have to use headphones most of the time, you cannot work barefoot unless you don’t mind the looks, you cannot just lay down in a sofa to think about hard problems unless you don’t mind the looks…
It’s all disadvantages.